1. Field of the Invention
This invention relates generally to motor vehicle accessories and more particularly to an improved apparatus and method of providing an air spoiler or cab fairing which may be mounted over the cab, or passenger compartment, of a pickup truck.
2. Description of the Related Technology
The cab portion of a conventional pickup truck typically has a rectangular appearance and a depth sufficient only to accommodate the comfortable seating of passengers. In order to maximize the cargo capacity in the pickup truck bed or "box", the cab typically terminates in a near vertical wall immediately behind the passenger seats. Although this arrangement tends to maximize the available cargo carrying space within the bed of the pickup truck, the rectangular cab structure projecting abruptly into the air stream tends to create a high drag force as the vehicle travels along the road.
In an effort to more smoothly direct the flow of air over the cab of the pickup truck, numerous streamlined fairing shapes have been proposed to reduce drag and improve vehicle mileage. These devices can also be decorative. Additional advantages include the reduction of air turbulence within the truck box, protection of the cargo carried within the box, and increased surface area of the vehicle roof so as to permit the mounting of lights, antennas or horns. Such fairings can also partially block the sun in order to keep the cab interior cooler and reduce glare. Unfortunately, such fairings or spoilers are seldom included in pickup trucks as they leave the factory, and so the device must be retrofitted to existing vehicles.
In the past, spoilers and fairings have typically been mounted by connecting the spoiler to both the cab and the truck box. This mounting arrangement presents several problems. First, mounting of the device is complicated since alignment between the mounting structures on the cab and on the truck box must be perfectly matched in order to fit properly with the fairing structure. Second, the cab and the box often behave as two discrete structures. Any differential movement between these two structures can result in cracking or warping of the fairing if the fairing is rigidly attached to both regions of the truck. Finally, the traditional mounting arrangement prevents the use of a conventional truck box cover since the cover is typically attached to the truck box in the same region in which the fairing is mounted. This creates the necessity of constructing a custom truck box cover, or more frequently, utilizing an existing truck box cover but failing to fasten it completely in the area behind the cab. This defeats the purpose of the box cover insofar as it permits moisture, sunlight and dust to enter the otherwise protected cargo area.
Examples of conventional pickup truck fairings and covers are shown, for example, in U.S. Design Pat. No. 281,487, issued to Chapman, in which the faired rear portion of the cab abuts the box cover. The fairing shown in the '487 patent could not be easily retrofitted to an existing vehicle, since it would require substantial modification of the body of the cab. U.S. Design Pat. No. 286,143, issued to Lund discloses an air spoiler for pickup trucks which may be easily retrofitted to an existing cab. However, the '143 design interferes with the perimeter of the existing truck box and would, therefore, make the use of an existing box cover impossible.
U.S. Design Pat. No. 294,242, issued to O'Neill shows a truck cover incorporating fairing arrangement, in which the fairing and the cover must be custom designed to fit together. Note that the truck cover abuts the fairing, with the fairing also serving as a portion of the cover itself.
U.S. Design Pat. No. 295,084, issued to Weber, depicts a retrofittable spoiler which supports a light bar. The mounting arrangement involves fastening a light bar directly to the sidewalls of the truck box, thereby requiring the use of a custom made cover for the box.